package main

func main() {
	println(lengthOfLongestSubstring("pwwkew"))
	println(lengthOfLongestSubstring(" "))
	println(lengthOfLongestSubstring(""))
	println(lengthOfLongestSubstring("abcabcbb"))
	println(lengthOfLongestSubstring("aab"))
	println(lengthOfLongestSubstring("dvdf"))
	println(lengthOfLongestSubstring("abba"))
}
